Single-dose pharmacokinetics of marbofloxacin in Egyptian Buffalo (Bubalus bubalis L.) steers

The objective of this study was to investigate the pharmacokinetics of marbofloxacin (MAR) following intravenous (iv) and intramuscular (im) administration of a 2.0 mg/kg body weight dosage to five healthy Egyptian buffalo steers. A crossover design was used with a washout period of 2 weeks. Blood samples were obtained at 0, 5, 10, 15, and 20 min and at 0.5, 0.75, 1, 2, 4, 6, 8, 10, 12, 24, 30 and 48 hours after marbofloxacin administration. The serum marbofloxacin concentrations were quantitated using a modified agar diffusion bioassay method. Marbofloxacin exhibited a relatively high volume of distribution at steady-state (Vdss = 1.77 L/kg), which suggests good tissue penetration, and a total body clearance (Cltot) of 0.18 L/kg-h, which is associated with a long elimination half-life (t(1/2 beta) = 7.52 h). Marbofloxacin was rapidly absorbed at a dosage of 2.0 mg/kg after im administration with an observed maximum serum concentration (C-max) value of 2.004 mu g/mL obtained at a time to peak concentration (t(max)) of 0.5 h, and an absolute bioavailability (F %) of 86.79 +/- 5.53 %. The protein-binding ranged from 22 to 24.6 % with an average of 23.4 %. In conclusion, single iv and im administered doses of marbofloxacin were well tolerated by Egyptian buffalo steers. A dosage of 2 mg/kg body weight might not be enough to treat infections caused by bacteria with minimum inhibitory concentration (MIC) at or above 0.2 mu g/mL, based on the calculated area under the inhibitory concentration (AUIC).